Method of concurrently producing visible and magnetizable indicia



3,484,318 VISIBLE AND /N|//V7'0/?$. FREDERICK R. NEUFELD MERLE P. PRATERATTORNEY F. R. NEUF'ELD ET AL CONCURRENTLY PRODUCING MAGNETIZABLEINDICIA Filed June 23 1966 Dec. 16, 1969 METHOD 0F G 3 4 F mm I F FUnited States Patent 3,484,318 METHOD OF CONCURRENTLY PRODUCING VISIBLEAND MAGNETIZABLE INDICIA Frederick R. Neufeld and Merle P. Prater,Vestal, N.Y.,

assignors to International Business Machines Corporation, Armonk, N.Y.,a corporation of New York Filed June 23, 1966, Ser. No. 559,954 Int. Cl.B31f 7/00; B41m /00 US. Cl. 156220 3 Claims ABSTRACT OF THE DISCLOSURE Aporous, coalescible polymer material film with a homogeneous dispersionof magnetizable particles is applied to the back side of an embossablenon-magnetizable substrate, such as paper. Impacting the paper with atype slug will produce a human readable character on the paper andconcurrently, by embossing the paper, compact the particles toward ahard platen to a degree Where they will produce a magnetic charactercorresponding in configuration to a mirror image of the human readablechar acter. This magnetic character will develop a signal levelsignificantly higher than the non-impacted areas when moved relative toand sensed by a magnetic transducer adjacent the exposed andcontinuously smooth side of the film.

This invention relates generally to a method of producing magnetizablebits or characters which are visible and magnetically detectable.

Generally stated it is an object of this invention to provide animproved method for producing visible magnetizable markings withoutrequiring the use of an external source such as a Magnetic Ink CharacterRecognition (MICR) ribbon.

More specifically it is an object of this invention to provide for anopaque, porous and coalescible semi-cured plastic emulsion film materialimpregnated with a magnetizable material which, when impacted by a typemember, produces a visible area in which the film clears, and in whichthe material of the film is compressed so that the concentration ofmagnetizable particles is increased sufficiently to provide a mark whichis easily detectable by a read head when magnetized.

Another object of the invention is to provide for an opaque, porous andcoalescible film impregnated with iron oxide particles to provide avisible and magnetically detectable mark when impacted by or against acharacter bearing element, as in a printer or the like.

Yet another object of this invention is to provide for an opaque, porousand coalescible polymer film homogeneously impregnated with particles ofa magnetizable material, and for impacting the film to provide visiblemarkings thereon having a concentration of magnetizable particles in theimpacted area which may be magnetized and readily detected by a magneticread head or the like.

It is also an important object of this invention to provide for coatingan opaque, porous and coalescible poly mer film with a high densitycoating of a magnetizable material and impacting the magnetizablematerial side of the film to force the magnetizable particles into thefilm so as to produce an embossing or compacting of the magnetizablematerial into the opaque, porous and coalescible film, such that it canbe readily detected by a magnetic read head from the rear surface of theopaque, porous and coalescible film after it has been subjected to amagnetic field.

In practicing the invention in accordance with a preferred embodimentthereof, an opaque, porous and coalescible film material comprising, byway of example, an open cell structure polymer film ofpolyacrylonitrile,

3,484,318 Patented Dec. 16, 1969 is homogeneously impregnated withparticles of magnetic iron oxide having a concentration on the order of10 percent, by introducing the iron oxide with the polymer particles inthe initial stages of manufacture. When such a film, either separatelyor bonded to a layer of paper or other similar embossable substrate, isimpacted such as by printing thereon by means of an electric typewriter,the printed or impacted area becomes visible, and the iron oxidedispersion is concentrated sufliciently by the impacting to produceoxide concentrations which when magnetized are readily detected by asuitable transducer or read head on the side of the film opposite fromwhere the material is impacted.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings.

In the drawings:

FIGURE 1 is a sectional view in part of an impregnated opaque, porousand coalescible film bonded to a sheet of paper in accordance with oneembodiment of the invention;

FIGURE 2 is the sectional view of the embodiment shown in FIGURE 1illustrating the impacting effect of a type slug or the like on theimpregnated film;

FIGURE 3 is the same sectional view as in FIGURE 2 illustrating thedetection of the magnetic character or bit by a read head;

FIGURE 4 is the same sectional view as in FIGURE 2 showing the relativeeffect of a spurious scratch or the like detected by the read head;

FIGURE 5 is a partial cross-sectional view illustrating anotherembodiment of the invention in which the opaque, porous and coalesciblefilm is provided with a magnetizable coating and bonded to a layer ofpaper or the like;

FIGURE 6 is the cross-sectional view of FIGURE 5 showing the effects ofimpacting the coated film by a type slug;

FIGURE 7 is the same crosssectional view as in FIG- URE 6 showing theimpacted area being detected by a magnetic read head; and

FIGURE 8 is the same cross-sectional view as in FIG- URE 6 showing therelative efiects that a scratch has on the read head.

Referring to FIGURE 1 of the drawings, it will be seen that a film 10 ofan opaque, porous and coalescible film material is homogeneouslyimpregnated with magnetizable material represented by the dots 12 in thefilm 10 and is secured to a sheet of paper or the like 14, being securedthereto by means of any suitable adhesive, for example, Eastman 910,Duco, Elmers Glue or other suitable polymeric adhesive.

The opaque, porous and coalescible film material may be of the typedescribed in Patent No. 2,846,727 which issued on Aug. 12, 1958, to M.F. Bechtold and which described a number of useful aqueous dispersionsof polymers suitable for use in practicing the present invention. Theopaque, porous and coalescible film is in accordance with one embodimenthomogeneously impregnated with a magnetizable material such as ironoxide which may be added to the aqueous polymer dispersion in theinitial step of manufacture. The iron oxide may be added in an amount onthe order of 10 percent by weight and may comprise particle sizes on theorder of .3 to .4 micron. If desired black ferrosoferric iron oxide mayalso be used which is acicular in form, having needle-shaped particleson the order of .55 by .08 micron. This impregnated material can befused or laminated to paper, plastic material or any number of othersuitable substrates.

When the laminated article is subjected to mechanical impact by animpact system such as a typewriter or printer, the impact of the typeslug embosses the paper 14 and produces a compressing of the opaque,porous and coalescible film in the area of impact 16 when the film isbacked up by a hard platen 11 as shown in FIGURE 2. Upon impact the filmcoalesces and the concentration of magnetic particles homogeneouslydistributed throughout the film can in the compressed area be increasedon the order of five times by compressing the film to approximately 20percent of it original thickness. When such impacting is done against ahard platen such as that of a typewriter or the like, and the opaque,porous and coalescible material is located adjacent to the platen, ahigh concentration of the magnetic particles is forced to the exposedsurface area of the film adjacent the platen. This occurs as the paper14 is embossed by the type slug 15 and in turn compacts and coalescesthe film from its inside surface. The surface concentration of magneticparticles forms in the impacted area a visible contrasting numerical oralphabetical character which is easily readable, the film in theimpacted area clearing the magnetic material showing up as a relativelydark area in contrast with the normally light color of the non-impactedportions of the film.

As a magnetic read head is moved past the opaque, porous and coalesciblefilm on the side which was adjacent the platen 11, a difference inmagnetic signals between the coalesced and non-coalesced areas may bereadily detected after the film has been subjected to a magnetic field.The crowding of the magnetic particles toward the exposed film surfacecauses a greater signal strength proportionally than the simple degreeof compression would indicate, because of the decrease in the signalproduced by remote magnetic particles, through the inverse square laweffect. If the matrix is magnetized either before or after impacting,the signal to non-signal ratio is very high.

Any spurious compression of the opaque, porous and coalescible film fromthe film side of the laminate would separate the magnetic material fromthe read head by some air gap, which in pre-magnetized materials woulddecrease any signal because of the inverse square law effect as may beseen by referring to FIGURE 4. The film is provided with a reasonabledegree of protection from being accidentally marked on the paper side,except by highly deliberate impact such as produced by a type slug orthe like, so that the chances of spurious marking of the laminate arerelatively low.

Referring to FIGURE 5 it will be seen that in another embodiment of theinvention the opaque, porous and coalescible film may be coated with alayer of high density magnetic material 31 and then bonded to a substrate such as the paper 32 or the substrate could be a film material ifdesired. When such a laminate is impacted as by a type slug 15, thepaper 32 is embossed with the outline of the character carried by thetype slug and the magnetic material of the film 31 is forced into thematerial of the opaque, porous and coalescible film 30. As shown inFIGURE 6 this brings the high density magnetic particles close to thesurface of the film nearest the platen 11 (.2 mil in a 1.0 mil film),producing both a visible outline of the character on the type slug andexhibiting a much more powerful magnetic signal than in the non-impactedareas.

Such an impacted area may be readily detected by means of a magneticread head 20 brought in contact with the film on the platent sidethereof in the impacted area as shown in FIGURE 7. If the matrix ismagnetized the signal is significantly greater in the impact, i.e. bitor character area than in the non-impact area, whether the magnetizationoccurs either before or after impacted.

As shown in FIGURE 8, compression of the opaque, porous and coalesciblefilm by means of scratches would have little effect, since in the signalarea the material is already compressed, and in the non-signal area thescratches do not produce any concentration of the magnetic particles onthe read head side of the film.

In practice, a .5 mil thick opaque, porous and coalescible film wasbonded to the magnetic oxide side of an audio recording tape. When themagnetic oxide was embossed into the opaque, porous and coalescible filmby printing an I with an electric typewriter, a visible character wasproduced on the exposed side of the film by the magnetic particles beingcompressed into the impacted area of the film. When the tape and thefilm laminate were passed by a magnetic read head, at approximately 40inches per second, with the opaque, porous and coalescible filminterfacing the head, a usable signal of 3 millivolts was produced bythe I typed on the film, with a signal to noise ratio of greater than10:1, the magnetic tape simulating the paper substrate and magnetic filmcombination.

Such an opaque, porous and coalescible film when impregnatedhomogeneously with iron oxide particles can be bonded to checks,mortgage slips, or other documents for correcting MICR checks orproducing MICR checks without requiring the use of a separate MICRtransfer ribbon as is usually done.

What is claimed is: 1. The method of concurrently producing visible andmagnetizable indicia, which comprises the step of:

providing a film of porous and pressure coalescible plastic butsubstantially uncoalesced polymer material having a substantiallyhomogeneous dispersion of particles of a magnetizable material therein,

applying the film to an embossable non-magnetizable substrate to providea composite article,

impacting the substrate with a character-bearing type member while thefilm is backed up by a hard platen to emboss the substrate and therebycompress the film in the impact area to approximately one-fifth itsoriginal thickness and concentrate the magnetizable particles just belowthe exposed surface of the film in a pattern conforming to the visibleconfiguration of such character While precluding embossment of saidexposed surface.

2. The method according to claim 1 characterized in that the filmcomprises a vinylidene type organic polymer.

3. The method according to claim 1 characterized in that the film is ofa type which while uncoalesced is substantially opaque and whencompressed is relatively clear, thereby to provide a visible character,which as viewed from the film side is a mirror image of the humanreadable character, to enable authentication of the visible humanreadable character to discourage and/or detect alteration.

References Cited UNITED STATES PATENTS 2,957,791 10/1960 Bechtold161-159 3,057,999 10/1962 Newman et a1 1l736.7 3,111,421 11/1963 Newmanet a1 ll736.7

ROBERT F. BURNETT, Primary Examiner W. J. VAN BALEN, Assistant ExaminerUS. 01. X.R.

